It is frequently desirable to provide a highly reliable source of power for electronic equipment. Computer and communication systems which supply critical services are therefor frequently powered by power sources whose reliability is enhanced by the use of redundant electronic components and/or standby battery power. It is also desirable to protect both batteries and connected circuitry from damaging currents which can exist in the event of circuit failure or other effects while, to the extent possible, maintaining a continuous supply of output power. It is also desirable to provide fault condition detection and signaling mechanisms which alert both locally and remotely-located maintenance personnel when trouble conditions occur, identifying the location and nature of the problem being experienced.